Radio receiving system



March 21, 1933.' A. w. c. BOLJAHN RADIO RECEIVING SYSTEM Filed Feb. 6, 1931 mwtm: vumm kmriq Patented Mar. 21, 1933 UNITED STATES.

PATET. OFFICE i ADOLF w. c. romhnn, or JERSEY cI'rY; N W JERSEY, ASSIGNOR To wIEEn 1 m, me,

, on NEW YORK, 1v. Y., A CORPORATION oEnELAwAEE RADIO REGEIVING- SYSTEM Application filed February 6, 1931. Serial No. 513,795.

My invention pertains in general to a: radio receiving system and especially relates to a form of combined wired radlo and space radio receiving system.

In space radio broadcast recelvlng systemsthe signal level" of the received signaling energy is extremely small, being of the order of a few microvoltsr On the other hand, in wired radio broadcasting systems the signal level is much higher, it belng not unusual to find signaling energy at the receiver of the order of one-half volt or more. It will be obvious that anyattempt to produce a combined space radio and wired radio receiver is confronted with the problem of the wide divergence of signaling energy values obtainable. In order to utilize a single receiving organization for the selective reception of both wired radio and space radio signals it would normally be necessary to alter the circuit constantsof the organization each time the organlzatlon is changed from wired radio to space radio reception in order to obtain uniform output.

One of the objects of my invention consists in providing a simple and; efficient system for receiving either wired or space radio signals.

Another object consists in producing a radio receiving system having a space discharge tube in which means are provided for producing different amplification values with respect to different values of input energy.

I accomplish these and other desirable objects in a novel type of radio receiving system having a space discharge tube in which a plurality of control grids are respectively connected to a plurality of dif -ferent sources of signaling energy of different values.

In the drawing I have diagrammatically represented one embodiment of the radio receiving system of my invention.

Referring to the drawing in detail, power lines 1 are connected to a source of light and power currents and carrier frequency current 2. The lines 1 and source 2 are indicative of a normal wired radio broadcasting system in which carrier frequency signals are impressed upon/a vcommercial light and power distribution network. A wired radio filter system 3 is connected to the power lines 1 'through'capacitive couplings 4. The filter system 3 may be of any type well known in the art, such as an'elec-I tromagnetically coupled three-mesh network for reception of carrier frequency signals at a selected frequency. .The filter 3 has a terminating impedance 5 of a proper value. .1 The output of the filter 3 is connected to the cathode 6 of a space discharge tube 7 and to a contact 8. An antenna receiving circuit 9 is inductively coupled .to a resonantcircuit comprising the inductancev 10 and capacitance 11. The tuned circuit 10-11 is of a conventional type for the selective re-' ception of spacevradio signals. The 'circuit 10-11 is connected to the cathode 6 and to a contact 12. V

Another contact 13 is provided between the contacts 8 and 12 and is connected to a resistance 14 provided for a purpose here-' inafter disclosed." The space discharge tube 7 is provided with a heater filament 15 and an anode 16. Intermediate the anode 16 and the cathode 6 are two control grids 17 and 18. Thecontrol grid 17 and the control grid 18 are mountedat different positions relative to the cathode 6 and are further designed to provide for different ampl'ification conditions. The control grid 17 is adapted to produce greater amplification than control grid 18. A switch having two contact blades :19 and 20 is positioned as shown so that the contact blade 19 can engage with either of the contacts- 12 or 13 and the contact blade 20 can engage with either of the contacts 8. or 13. The contact blade 19 is connected to the control grid 17, while the 'contact blade 20 is connected to'the control grid 18. The heater filament 15 is connected. through a; transformer 21 to the commercial alternating current power lines 1 to derive energy for heatingthe cathode 6 to emit electrons. A full wave rectifier tube 22. is provided and has plates 23 connected through a high voltage transformer 24 to' the. powerli'nes 1 and a filament connected through a low voltage transformer 26 to the power lines 1. The plate 16 is connected through a resistance 27 to a mid-point of the secondary of the transformer 26. The cathode 6 is connected to the mid-point of the secondaries of the transformers 21 and 24. The rectifier tube 22 serves as a source of high potential direct current for the anode 16. The resistance 14 is connected to the circuit from the anode 16 and provides a source of potential which may be selectively applied to either of the control electrodes 17 or 18 through the switch 19-20 and which will be less positive than the potential applied to the anode 16. The output 28 is connected to a suitable work circuit which may include a demodulation device and a translating device.

When it is desired to operate the radio receiving system of my invention for the reception of wired radio signals, the switch 19-20 will be in a position such as shown in the drawing. In this position the grid 17 will be connected to contact 18 and be positively energized while the grid 18 will be connected through contact 8 to the output of the filter system 8. The filter system 3 will therefore provide signaling energy to the grid 18 and will control the space discharge from cathode 6 to anode 16. The positive potential applied to the grid 17 will prevent the accumulation of negative charges thereon whichwould result in the repulsion of electrons.

To operate my system for the reception of space radio signals, the switch blade 19 is movedto contact 12 and'the switch blade 20 is moved to contact 13.- In this position a positive potential would be applied to the grid 18 while the signaling energy from the circuit 1011 will be applied to the control grid 17. Since the control grid 18 is more distant from the cathode 6 than the grid 17, it will be obvious that a greater amplification of .the space radio signals will result. The exact spacing ofthe grid 17 and 18 in the tube 7 can be arranged in a manner such as to produce a constant energy value at the ouput 28, irrespective of whether the system is operating for reception of wired radio signals or space radio signals.

It will now be obvious that I have provided a novel radio receiving system for the 1. A radio receiving system comprising, a plurality of different sources of signaling energy, a space discharge tube including a cathode and an anode, a plurality of control grids interposed between said cathode and anode, a source of steady otential, and means for connecting one of said control grids selectively to one of said sources of signaling energy or to said source of steady potential and the other of said control grids selectively to the other of said sources of signaling energy, or to said source of steady potential.

2. A radio receiving system comprising, a plurality'of different sources of signaling energy, a space discharge tube including an anode and a cathode, a plurality of control electrodes positioned between said cathode and anode but at different distances with respect to said cathode, a source of steady potential, and means for connecting one of said electrodes selectively to one of said sources of signaling energy or to said source of steady potential and the other of said control grids selectively to the other of said sources of signaling energy, or to said source of steady potential.

3. A radio receiving system comprising, a space radio tuning system, a wired radio tuning system, a space discharge tube having an anode and a cathode, a source of positive potential, a control electrode positioned between said anode and cathode, means for selectively connecting said control electrode to said space radio tuning system orto said source of positive potential, a second control electrode positioned between said anode and cathode, and means for selectively connecting said second con,- trol grid to said'wired radio tuning system or to said source of positive potential.

ADOLF W. C. BOLJAHN.

5}. selective reception of either wired radio or space radio signals in which means are provided for maintaining a substantially constant operating characteristic. AlthoughI have shown a preferred embodiment of my invention, I do not wish to be limited thereto except insofar as may be pointed out in the appended claims.

What I claim as new and original and desire to secure by Letters Patent of the United States is: 

